Laser conversion of electrical properties for silicon carbide device applications

A direct conversion technique has been demonstrated to produce highly conductive tracks on silicon carbide by irradiating it with a laser beam. It is found that laser irradiation of insulating silicon carbide substrates decreases its resistivity from 1011 to 10−4 Ω cm. Scanning electron microscopy of laser-irradiated α-silicon carbide substrate reveals dispersed globules on the irradiated track. The atomic force microscopic images of the tracks indicate the conversion of larger structures into smaller, more round-shaped structures suggesting the formation of globules. However, laser irradiation of silicon carbide conductors in the presence of pure oxygen transforms the conducting track into an insulator. The effect of annealing on the electrical properties of the laser-generated conducting tracks is also examined. This technique provides a means of directly writing conducting and insulating tracks on silicon carbide to produce electronic devices for high temperature applications.